Winding device comprising electrostatic charging means and method for fixing a multi-layered film

ABSTRACT

The present invention relates to a device for winding up web-shaped material ( 35, 40, 41 ). This web-shaped material ( 35, 40, 41 ) is particularly film that is wound up on winding cores ( 7 ). The device for winding up web-shaped material ( 35, 40, 41 ) is equipped with at least one device for electrostatically charging ( 38, 42 ) the web-shaped material ( 35, 40, 41 ). Said device for electrostatically charging ( 38, 42 ) the web-shaped material ( 35, 40, 41 ) is arranged in such a manner with respect to the web-shaped material ( 35, 40, 41 ) and the winding core ( 7 ) that it exposes the web-shaped material ( 35, 40, 41 ) to an electrical field before it reaches the winding core ( 7 ).

This is a nationalization of PCT/EP2004/004803 filed May 5, 2004 and published in German.

The present invention relates to a winding device according to the preamble of the main claim 1. Winding devices are known from a multitude of published prior art of which only the patent application WO 99/06313 and US 5848761 have been mentioned as examples. Winders are usually categorized as contact winders and turret winders.

Among these winders the following devices must be highlighted here:

-   Devices for winding web-shaped material—particularly film—on winding     cores, that are provided over at least one device for     electrostatically charging the web-shaped material.

The present invention is based on these devices.

In the devices described in the patent applications U.S. Pat. No. 4,852, 820 and DE 102 02 462, the device for electrostatically charging the web-shaped material is used for holding down the web-shaped material on the initial winding sleeve. In this manner it is possible to hold down the initial section of the web-shaped material on a winding core without the help of adhesives. In technical jargon, this method is called “adhesive-free initial winding” and has high economic value because an initial winding process of such type can be executed fully automatically and additionally without the application of solvents on the web-shaped [handwritten correction made to the source; originally said “band-shaped”] material.

As a rule and also in the patent application DE 102 02 462, the afore-mentioned device for electrostatically charging the web-shaped material is usually formed as a beam-shaped electrode that can overcoat the width of the web-shaped material. In all applications and published prior art, they are illustrated in immediate proximity to the winding core and they charge the film with an electrical field when they reach the winding core.

The spatial proximity to the winding core is highly recommended since the strength of electrical fields strongly reduces as the distance from the electrode increases and ideally the biggest possible field effect should be available during the initial winding process. Therefore, the patent application DE 102 02 462 recommends arranging the means for electrostatically charging the web-shaped material as close as possible to the initial winding position, and/or within a small close and constant distance from the winding core during the initial winding process by means of a special displacement of the position of the electrode.

The devices specified in the preamble of the present patent application have proved to be of value during the “adhesive-free initial winding process.” However, like all winding devices of prior art, they exhibit disadvantages during the entire winding and cutting processes when several layers of film or film tubes have to be wound up. In this connection, it must be emphasized that these requirements are by no means unusual because winding devices often wind up the film that is just extruded from blown film extrusion plants. This film leaves the die head as film tube and is wound up either directly as a film tube or is severed into two film webs that are frequently wound up as double layers. In the following description these multi-layered material webs are also called layers of material webs. Film rolls are also known in which more than two material webs are wound up.

The reason for the afore-mentioned disadvantages is that at high winding speeds air gets trapped and is subsequently wound up in between the said film layers or in the film tubes. This gives rise to unattractive, too voluminous and telescopic film tubes, thus finally even causing the interruption of the winding processes. In case of film tubes, the shape of the initial section of the film during its transport through the winding device is referred to, partly metaphorically as “fish mouth.” Additional defects with regard to quality come into existence in case of too uneven and unattractive slits at the cutting point (while cutting off the film web perpendicular to its conveying direction) when air gets trapped between the layers that are to be cut. Even film tubes are referred to as multi-layered material webs in this patent application.

The objective of the present invention is to suggest a device that reduces the chances of air getting trapped in-between multi-layered, web-shaped material when the latter is being wound up.

This objective is achieved by

-   arranging at least one device for electrostatically charging the     web-shaped material in such a manner with respect to the web-shaped     material and the winding core that it exposes the web-shaped     material to an electrical field before it reaches the winding core.

The ability of different layers of material to join one another with great stability when charged electrostatically is greatly surprising. Furthermore, it must be mentioned that for improving the initial winding process an electrical field can also be used on the winding core without any interference from the means according to the invention for electrostatically charging the web-shaped material.

In the sense of this invention a winding core can be a winding sleeve or a different body shaped like a rod or a circular cylinder.

In case of different types and sizes of winders, it is advantageous to insert the film at different mounting positions and distances from the winding sleeve along its transport path. However, in general, it is useful if the electrical field joins the film layers to one another before they reach the cutter.

In case of a contact winder, the roller that guides the film before it reaches the winding core is the contact roller.

The process of charging the film electrostatically while passing through the rollers has proved to be greatly valuable.

Modern winding devices often have a multitude of such suitable deflecting or web guide rollers. These can also be arranged upstream to the winding device on the transport path of the web-shaped material.

Additional preferred embodiments of the invention are specified in the present description and in the claims. The individual figures of the drawing illustrate:

FIG. 1 a perspective view of a storage device according to the invention

FIG. 2 a perspective view of the mounting device of the winding device

FIG. 3 a a section of the perspective view of the device illustrated in FIG. 2 that shows a section of the holding head of the mounting device.

FIG. 3 b a view of the lock

FIG. 4 a perspective view of the parts of the winding device that guide the winding sleeves

FIG. 5 the same perspective view as illustrated in FIG. 4 in which the winding sleeve is located in the winding position.

FIG. 6 a view of a deflecting roller on which the means according to the invention are provided for electrostatically charging the web-shaped material.

FIG. 1 illustrates a storage device 1 according to the invention that comprises of a drum 2 suspended between the holding plates 3 on the front sides of the drum. The plates 4 which are connected to one another by the traverse member 5 form the front sides of the drum 2. The plates 4 comprise of recesses 6 for mounting the winding sleeves 7. The torsional moment for the rotation of the drum 2 is provided by both the drives 10. Two drives 10, of which only one can be seen completely, are used in this embodiment since the working width of the winder is relatively big. The drives 10 comprise of the motors 8 and the gear unit 9.

The insert sheets 11 for inserting the winding sleeves 7 into the storage device 2, the linear cylinder 12, the knife protection 13 and the traverse member 14 can also be seen in FIG. 1. The axis 41 of the drum 2 is formed by the drum traverse member 5, which connects the plates 4 to one another. The transport of the winding shaft into the storage device 1 is carried out by the rotation of the drum 2 around the axis 17.

FIG. 2 illustrates an additional functional element of the winder—the mounting device 15 for the winding shafts. The most substantial parts of the mounting device 15 are the holding arms 16 that can be swiveled around the axis 17 around which the contact roller 18 also rotates. The force required for the swiveling movement is provided by the pneumatic cylinders 19, which are hinged at the connecting points 20 to the holding arms 16 and at the connecting points 21 to the machine frame that is not illustrated here.

In the upper section of the holding arms, the holding heads 22 can be seen that can take over the winding shafts 7 from the storage device 1. In FIG. 2, the holding heads 22 are located at the transfer position at the upper end of the holding arm 16. The winding shaft is placed in the mounting position 23 of the holding head 22 and is locked in place with the help of the lock 24. The lock 24 is illustrated in FIG. 3 b. It is shaped to suit its purpose of locking the winding shaft 7 in place. The cylinder 25 pushes the lock over the winding shaft 7, thus locking the latter. The force of this cylinder 25 is transferred by means of the connecting device 30, as illustrated in FIG. 3 a. The cylinder 25 is attached to the holding head 22.

The holding heads 22 can be displaced along the holding arms 16 in the vertical direction. In this manner the winding shaft 7 can be placed on the contact roller 18. This position 34 of the winding sleeve—the so-called initial winding position of the illustrated contact winder—is illustrated in FIG. 4. The force for changing the position of the holding heads 22 in relation to the holding arms 16 is applied by the cylinders 26 that transfer the required force onto the holding head 22 using the rod 27 and the linkage 18.

FIGS. 4 and 5 illustrate the entire progression of a winding sleeve 7 in a contact winder. The storage device 1 and the mounting device 15 are also illustrated in this connection. In addition to the components already illustrated in FIG. 1 to 3, the bearing rail 27 and the laying arm 28 are also illustrated here. On the bearing rail 27, which is designed to be continuously straight, the winding shaft is located in its winding position 31 illustrated in FIG. 5. After the old roll has taken up sufficient web-shaped material, it is moved along the bearing rail 27 of a holding and transport device, that is not illustrated here, up to the holding point 32 of the laying arm 28 that can be swiveled around the axis 29. With the help of this laying arm 28, the heavy winding sleeve supplied with web material can be pivoted away onto another transport device. The force required for this purpose is applied by a cylinder (not illustrated here) that is hinged onto the bearing eye 33.

Additional details of the winding process and the transport of the winding shafts through a contact roller are known to those skilled in the art and hence do not require a more elaborate explanation.

The material web or the film 35 is illustrated only in the FIGS. 4 and 5, where the initial section of the film 36 can be seen only in FIG. 4. The last deflecting roller 37 located before the deflecting roller 18 is also illustrated. Opposite to it, the electrode 38 is located, which is attached to the machine frame (not illustrated here) using holders 39. The electrode enables the advantageous application of an electrical field to the film tubes. The adhesion of the two tube walls to one another is referred to as “blocking.” The positioning of this electrode 38, which is an embodiment of the means for electrostatically charging the web-shaped material is the object of the present invention.

Therefore FIG. 6 illustrates yet another view of a deflecting roller 39 of an additional embodiment of the present invention on which means are provided for electrostatically charging the web-shaped material.

These means comprise of the electrode 38 and the mounting device 42. Above this deflecting roller 39, the last deflecting roller 37 is located upstream in the transport direction z of the web-shaped material. The outlined guiding of the deflecting roller is marked with the reference symbol 43. It can be provided with additional means for electrostatically charging the roller 39 in order to increase the potential difference of the electrode 38 or to provide the film with a potential independent of the electrode 38. The afore-mentioned blocking effect of the two tube walls according to the invention can also be achieved by the exclusive application of charge to the roller. The web-shaped material guided over the deflecting roller 39 comprises of the inner 40 and the outer 41 film web. Since the electrode is not charged, both the film webs 40, 41 diverge from one another. This divergence of the two film webs is somewhat exaggerated in the illustration. List Of Reference Symbols 1 Storage device 2 Drum 3 Holding plate 4 Plate 5 Traverse member 6 Recess 7 Winding sleeve 8 Motor 9 Gear unit 10 Drive 11 Insert sheet 12 Linear cylinder 13 Knife protection 14 Traverse member 15 Mounting device 16 Holding arm 17 Axis 18 Contact roller 19 Pneumatic cylinder 20 Connecting point 21 Connecting point 22 Supporting head 23 Mounting point 24 Lock 25 Cylinder 26 Cylinder 27 Bearing rail 28 Laying arm 29 Axis 30 Connecting device 31 Winding position 32 Holding point 33 Bearing eye 34 Initial winding position 35 Film 36 Initial section of the film 37 Last deflecting roller before contact roller 18 38 Electrode 39 Next deflecting roller 40 Inner film web 41 Outer film web 42 Charging unit 43 Guiding of the deflecting roller 44 Bearing point of the winding sleeve 45 46 47 48 49 50 51 52 53 54 55 56 

1. Device for winding up of web-shaped material (35, 40, 41)—particularly film, on winding sleeves (7), that comprises of at least one device for electrostatically charging (38, 42) the web-shaped material (35, 40, 41) characterized in that at least one device for electrostatically charging (38, 42) the web-shaped material (35, 40, 41) is arranged in such a manner with respect to the web-shaped material and the winding sleeve (7) that it exposes the web-shaped material (35, 40, 41) to an electrical field before it reaches the position of the winding core (7) in the transport direction (z) of the web-shaped material (35, 40, 41).
 2. Device pursuant to claim 1 characterized in that at least one device for electrostatically charging (38, 42) the web-shaped material (35, 40, 41) is provided, which is arranged in such a manner with respect to the web-shaped material (35, 40, 41) and the winding core (7) that it exposes the web-shaped material (35, 40, 41) to an electrical field in the transport direction (z) of the web-shaped material 30 centimeters before it reaches the winding core (7).
 3. Device pursuant to the preceding claim characterized in that at least one device for electrostatically charging (38, 42) the web-shaped material (35, 40, 41) is provided, which is arranged in such a manner with respect to the web-shaped material (35, 40, 41) and the winding core (7) that it exposes the web-shaped material (35, 40, 41) to an electrical field in the transport direction (z) of the web-shaped material 50 centimeters before it reaches the winding core.
 4. Device pursuant to claim 1 characterized in that at least one device for electrostatically charging (38, 42) the web-shaped material (35, 40, 41) is provided, which is arranged in such a manner with respect to the web-shaped material (35, 40, 41) and the winding core (7) that it exposes the web-shaped material (35, 40, 41) to an electrical field before it reaches the last roller (18) of the winding device guiding the film before reaching the winding core (7).
 5. Device pursuant to the preceding claim characterized in that at least one device for electrostatically charging (38, 42) the web-shaped material (35, 40, 41) is provided, which is arranged in such a manner with respect to the web-shaped material (35, 40, 41) that it exposes the web-shaped material (35, 40, 41) to an electrical field when it runs on the last deflecting roller (37), that is upstream to the last roller (18) of the winding device and that guides the film before reaching the winding core (7).
 6. Device pursuant to claim 4 characterized in that at least one device for electrostatically charging (38, 42) the web-shaped material (35, 40, 41) is provided, which is arranged in such a manner with respect to the web-shaped material (35, 40, 41) that it exposes the web-shaped material (35, 40, 41) to an electrical field before it runs on the last deflecting roller (37).
 7. Device pursuant to claim 6 characterized in that at least one device for electrostatically charging (38, 42) the web-shaped material (35, 40, 41) is provided, which is arranged in such a manner with respect to the web-shaped material (35, 40, 41) that it exposes the web-shaped material (35, 40, 41) to an electrical field when it runs on a deflecting roller that is upstream to the last deflecting roller (37).
 8. Process for winding multi-layered, web-shaped material (35, 40, 41), preferably of film, in which the web-shaped material is exposed to the influence of an electrical field and thus is held down on components of the film roll characterized in that multi-layered web-shaped material (41) is wound up and that at least one layer of the web-shaped material (35, 40, 41) is laid down on at least one other layer of web-shaped material (40) during transport through the device for winding up web-shaped material.
 9. Process pursuant to the preceding claim characterized in that at least one web of material (41) is laid down on at least one other web of material (40).
 10. Process pursuant to claim 8 characterized in that one wall of a tube of material is laid down on the other wall.
 11. Process pursuant to claim 8 characterized in that the multi-layered web-shaped material (35, 40, 41) is exposed to an electrical field before it reaches the cutting point (12, 13).
 12. Process pursuant to claim 9 characterized in that the multi-layered web-shaped material (35, 40, 41) is exposed to an electrical field before it reaches the cutting point (12, 13).
 13. Process pursuant to claim 10 characterized in that the multi-layered web-shaped material (35, 40, 41) is exposed to an electrical field before it reaches the cutting point (12, 13). 